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## LU Factorization by Doolittle's method

version 1.0 (1.08 KB) by

LU factorization of a square matrix.

3.47619
22 Ratings

Updated

This program factorize(decompose)the square matrix of any size into a product of a Lower-triangular matrix (L) and an Upper-triangular matrix (U). All the elements of the main diagonal in the L matrix are ones, (Doolittle's method).

This factorization is very helpfull in solving different mathematical problems and problems in linear control systems.

Campos Moises

### Campos Moises (view profile)

Muy buen programa, gracias

Campos Moises

Duster Smith

PIAK

### PIAK (view profile)

I want to algorithm for this program.

abdullah alzkarneh

### abdullah alzkarneh (view profile)

thx Dr.yaseen you are creative I hope many successes to you

Husam Aldahiyat

### Husam Aldahiyat (view profile)

No comments, messes workspace, C style programming. This file should be removed from the FEX.

Peter Androv

Thanks, Excellent.

noppanun suksomboon

Lara Evans

It was usefull for me.

Tim Davis

See my comments below - I didn't select a rating in my last review.

Nice

Tim Davis

The file doesn't have any comments, so it isn't useful as an educational tool. The lutx.m function in Cleve Moler's NCM toolbox (http://www.mathworks.com/moler/ncmfilelist.html) is much better code (simpler, easier to read, and well commented). Plus, lutx.m comes with extensive documentation in Cleve's book which you can download for free. The file here has none of that.

Cleve even has an LU GUI in which you can watch the LU factorization, with pivoting, occur before your very eyes.

So for educational use, there are far far better alternatives.

Of course, for dense or sparse LU factorization this function (if it were converted into a function) would not be used in production code since it's far far slower
than the MATLAB built-in LU.

So why is it here? What purpose could it serve? Why does the File Exchange have a plethora of Gaussian Elimination variants such as this one?

I would kindly suggest that this file be withdrawn.

amir khan

very good

John Lee

This is an excellent program to explain the LU decomposition.

i need this method to finish my thesis about dispatching

Andres Fernandez

It seems written for visual basic, it doesn't use the Matrix Algebra MatLAB offers at all.

John D'Errico

Why use a script that does an LU factorization in a completely unvectorized fashion? Especially when there is already a far faster implementation of an LU in matlab itself? Beware, this clears your workspace, then makes you type in the matrix. Its just the author's homework assignment.

masoume azarpour

Duane Hanselman

Not a function. Clears the base workspace without warning! Poorly duplicates what the function LU does in MATLAB.

Camilo Ardila

Alex Roberto

Dani Patrick

Hasan Ali

John Michael

Good, as showing the basics of decomposition

Joseph Peter

Good For implenting Doolittle's method (the elements of the main diagonal are ones).

Duane Hanselman

1) This is a script file, not a function.
2) Why use this function over the builtin MATLAB function LU?
3) Many For Loops in the script are not needed, e.g., you can start L with L=eye(m); rather than with a For Loop that does the same thing.
4) Does your code implement pivoting?
5) Nice homework solution for a beginning numerical methods class.

MATLAB 7 (R14)
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